DIY : PTFE line- tank to HPFP + inline fuel filter upgrade

[doublespaces]

The fitting most use has a 1/8 npt port. The stock LP fuel sensor seals with an o-ring so I was not comfortable using a NPT fitting for that. On the flip side multiple people have used it with no issues. I may address that down the road. Ill see where this takes me first.

Oh right that sensor, I forgot. I wonder if there is an alternate sensor that could be used.

 

[martymil]

What you can also do is get a dash 6 steel weld on fitting, cut all the bends out and get it welded on just before the sensor.

This will get rid of all the restriction, but its a lot more expensive than using the npt fitting with a little gas thread tape.

You can also cut the bends out and use an olive compression tube fitting on the end of the factory line just before the
sensor which is my least favourite but I've seen it done and that's what made me put this setup together.

 

[Twisted Tuning]

This is interesting "Idea" but personally don't recommend it... The HPFP is the weak link not the screen in the line it is just another fail safe to protect injectors. You still left the biggest restriction in the entire fuel system which is the in tank filter assembly.

I like the outside the box thinking but it's always important to do testing and make sure these mods yield results. Your install looks very clean and well thought out though I'll give you that for sure good work!

I've personally removed the hpfp screen on 4 cars not including mine (Which I did many moons ago). And every time rail pressure recovered with no changes other than that. So that screen affects the HPFP more than people think.

Sure, I do 100% agree That the HPFP is still and certainly a flow limiting factor beyond a point.

But real data showed improvement on my end. With the removal of the screen.

 

[Twisted Tuning]

This fuel rail keeps coming back to me. Why is it that BMW used the fuel rail from the N53 on the 135i and 1M N54 cars which is a different part number from the fuel rail thats on all other N54 3, 5, 7 series, X6, and Z4 cars ?

Logically since the 1M is rated the most powerful N54 car using the N53 fuel rail, would this be suggesting the N53 fuel rail part number has better flow ? I cant fine any physical differences between the two part numbers from a picture view.

Willing to bet there is no real difference.

Thanks I appreciate that! I agree you see hack jobs more often than not.


I am still breaking in my clutch but I expect between 300-500. If I remember martymil gained about 500. A local pulled his filter and drilled his rail and gained around 300. I will say his pump was not struggling as much as mine so I am curious to see the results. I will post logs when I get done


Thank you for your write up!!


The fitting most use has a 1/8 npt port. The stock LP fuel sensor seals with an o-ring so I was not comfortable using a NPT fitting for that. On the flip side multiple people have used it with no issues. I may address that down the road. Ill see where this takes me first.


Thank you. Do you still plan on a n54 hpfp upgrade?



Thank you, but I am definitely not the first to pull the filter and drill the rail. It should help 300-500psi on the high side. Is it a huge change? No, but any gain on the high side is good with me. I agree the HPFP is is weak link but seeing as there is no solid HPFP upgrade this is why I chose to do this. I am not a fan of port injection and would like to stay DI only. I get the filter being a fail safe that is why I chose to add a larger inline filter. I imagine some of the gains from the filter becoming dirty. As for the tank filter assembly I know y'all and a few people in the past have developed one but I haven't seen results. This is definitely not the upgrade for someone looking for huge power. I am hoping to get around 550ish on an ethanol mix.

Yes, N54 pump still is on table.

Has anyone seen the hpfp filter look gunked up at all when it is removed?

A couple I've personally removed yes but a couple others were not. But both showed pressure improvements

 

[veer90]

Has anyone seen the hpfp filter look gunked up at all when it is removed?

Mine was clean.

People forget the in-tank assembly is a pressure regulator AND a filter. Combined with the sock on the fuel pump, any fuel is already filtered twice before it reaches the HPFP.

 

[BOosted 335i]

Can the filter for Hpfp be removed while still on car?Also as from post above,the fuel is already being filtered prior to hpfp.yes having another filter will HELP prevent issues but creates more restriction.seems a lot of people have done this without negatives,seems to be more positive.would like to see more results from others.

 

[veer90]

Can the filter for Hpfp be removed while still on car?Also as from post above,the fuel is already being filtered prior to hpfp.yes having another filter will HELP prevent issues but creates more restriction.seems a lot of people have done this without negatives,seems to be more positive.would like to see more results from others.

Yes remove intake, charge pipe, TB, and hpfp feed line. make a wire hook, get in there with needle nose pliers and fish it out.

 

[martymil]

There is no restriction with this new filter, it has over 10x + the surface area and flow than the factory one.

Its only there just as a precaution if the aftermarket lines fail, since the OP went with PTFE lines the filter is an overkill but hey why not ?

Factory lines are plastic and metal, pretty much no chance of failure except when foreign material enters when the system is pulled apart or on reassembly.

The orbital di pump was never designed to work this hard or needing this much fuel on the low pressure side as the pump is definitely starving since the pressure goes up when filter is removed, if anything you are extending the life of the pump.

 

[martymil]

Guys if your going to do this mod make sure you reset hpfp adaptations using inpa

Mhd didnt work for me on a number of cars especially where i installed a shotgun you can clearly see the difference before and after on the rail pressures

Best way to do this is

Filter first reset and test
Drill fuel rail reset and test
Upgrade fuel line reset and test

In that order or all at once otherwise its a waste of time.

Go for a dyno session or at least 3 to 4 hwy 3rd gear pulls to let it adapt

 

[Blaster3500]

Guys if your going to do this mod make sure you reset hpfp adaptations using inpa

Mhd didnt work for me on a number of cars especially where i installed a shotgun you can clearly see the difference before and after on the rail pressures

Best way to do this is

Filter first reset and test
Drill fuel rail reset and test
Upgrade fuel line reset and test

In that order or all at once otherwise its a waste of time.

Go for a dyno session or at least 3 to 4 hwy 3rd gear pulls to let it adapt

Interesting. Thank you for the advice!

 

[martymil]

I had a couple of pm's about the diy though ill post it up so the info can be found all in one place

What i was trying to say if your going to do only one mod at a time thats the order you want to do it in or all at once thats all

 

[doublespaces]

Has anyone seen the hpfp filter look gunked up at all when it is removed?

This was mine. Car has 60k miles on it, not sure about the pump. E54 for about 3k, stage 2 bucketless.

 

[martymil]

just to show you guys how restrictive the line is on the bends

 

[martymil]

Roughly reduced to half on what goes into the pump on the bends

Flow restriction hmm I wonder.

 

[Lifestyler]

So they are improvments in rail pressure when remove hpfp Filter only ? Or Just when Drill fuel fuel rail to?
Iam on ST 6466
Stg3 custom lpfp (2 walbros )
All Upgrade fuel Lines from fuel IT
Pi with fpr and Return .

Sometimes rail pressure Drops when i Turn up the boost 35+ on e70ish

Any Suggestionen ?

 

[Lifestyler]

Are U Upgrade the Line from hpfp to fuelrail to?

Roughly reduced to half on what goes into the pump on the bends

Flow restriction hmm I wonder.

 

[martymil]

The biggest improvement is with the filter removal and the line helps too

No need to upgrade hpfp to fuel rail as the injector holes on the fuel rail are way smaller

Do not drill these bigger unless you have a double barrel shotgun kit

 

[Lifestyler]

The biggest improvement is with the filter removal and the line helps too

No need to upgrade hpfp to fuel rail as the injector holes on the fuel rail are way smaller

Do not drill these bigger unless you have a double barrel shotgun kit

So i have a small pice from the fuel Line into the hpfp that oem hardline where the fuel IT Line connects to with the quick Connect . So i do a custom Line an6 right ?

 

[martymil]

This is the one

This is the single biggest improvement

The line helps a little, yes an6

 

[BOosted 335i]

This was mine. Car has 60k miles on it, not sure about the pump. E54 for about 3k, stage 2 bucketless.

Doublespaces,
so it sounds like you have been running like this with no added inline filter correct?